Bubbling heard from toilet when refilling tank

My glorious 4 yo decided that it was neat watching things spin in the toilet and flushed a 3" x 1" x 1" plastic cap which cooperated by spinning and draining.

Unfortunately it got stuck in the bend of the toilet and would not come out using a auger or snake. I dismantled the toilet, leaving the tank in the tub and took the base out to the yard and blew water from the hose in reverse to pop it out.

While putting it all back together, the flange broke and had to be replaced with a PVC flange extender and the wax seal replaced. Everything works but when the tank is refilling it does so very slowly and I can hear bubbling in the tank but cannot see anything.